A motor seat device, such as the device disclosed in DE 41 08 295 A1 includes a displacement motor for displacing a motor vehicle seat in a forward or backward direction, a lift motor for moving the seat up and down and an incline motor for adjusting the angle of incline of the backrest of the seat. Data for operating the corresponding motors in reaction to a presetting process is stored in a pre-setting memory. A memory drive device drives the motors according to this operating data. By operating a manual switch device the motors are driven by a manual drive device. Controlling the motors in the event of actuation of the manual switch device when the motors are driven by the memory drive device is carried out by having a control mechanism process the operating data issued from each motor during its inertia rotation as signals in the same direction as directly before the inertia rotations of the relevant motors.
The adjusting devices of modern motor vehicle seats have self-locking displaceable elements in order to ensure the security of the vehicle seat in the event of a crash and to prevent the seat from being moved forwards by crash forces. As a result of the self-locking action of the displaceable elements, the adjusting devices of modern vehicle seats have a tendency to act sluggishly or slow. As such, the problem of errors in the start-up position through inertia rotations of the adjusting systems with the driving motors is rather less. It is questionable whether the accuracy of the determination of the actual position of the adjusting devices is adequate for approaching the stored position.
The object of the present method and device is therefore to improve the accuracy of determining the actual position of a part of a motor vehicle seat which can be displaced by a drive device without increasing the costs of sensors for detecting the position or impairing the self-locking properties of the adjusting device.